Methods and apparatus for achieving low coding rates

ABSTRACT

In an aspect, an apparatus may receive content to be transmitted and generate a first turbo encoded codeword from the content through use of a first turbo encoder. The apparatus maybe further configured to generate an interleaved codeword based on the first turbo encoded codeword through use of an interleaver, generate a second turbo encoded codeword from the interleaved codeword through use of a second turbo encoder, and transmit at least a portion of the second turbo encoded codeword. In an aspect, an apparatus may receive data including outer turbo encoded, interleaved, inner turbo encoded content. The apparatus may generate a first decoded instance of the data, generate a de-interleaved instance of the data based on the first decoded instance of the data, generate a second decoded instance of the data from the de-interleaved instance of the data, and perform a CRC on the second decoded instance of the data.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application Ser.No. 62/448,930 entitled “METHODS AND APPARATUS FOR ACHIEVING LOW CODINGRATES” filed on Jan. 20, 2017, which is expressly incorporated byreference herein in its entirety.

BACKGROUND Field

The present disclosure relates generally to communication systems, andmore particularly, to methods and apparatus that facilitate achievinglow coding rates for data transmission, e.g., using turbo encoders.

Background

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources. Examples of suchmultiple-access technologies include code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example telecommunication standardis 5G New Radio (NR). 5G NR is part of a continuous mobile broadbandevolution promulgated by Third Generation Partnership Project (3GPP) tomeet new requirements associated with latency, reliability, security,scalability (e.g., with Internet of Things (IoT)), and otherrequirements. Some aspects of 5G NR may be based on the 4G Long TermEvolution (LTE) standard. There exists a need for further improvementsin 5G NR technology. These improvements may also be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

In many communication systems, improved transmission reliability ishighly desirable. To achieve enhanced transmission reliability, codingschemes and/or encoders that may allow achieving low mother code ratesare desirable.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

Various features and aspects that facilitate achieving low coding ratesfor data transmission, e.g., using turbo encoders, in a communicationsystem are described. In an aspect of the disclosure, a method, acomputer-readable medium, and an apparatus are provided. The apparatusmay be configured to receive content to be transmitted, the contentincluding source data portion and a cyclic redundancy check (CRC)portion, and generate a first turbo encoded codeword from the contentthrough use of a first turbo encoder, where the first turbo encoder maybe associated with a first code rate. The apparatus may be furtherconfigured to determine whether an intended code rate for the content tobe transmitted is less than the first code rate. In one configuration,when the intended code rate is determined to be less than the first coderate, the apparatus may be further configured to generate an interleavedcodeword based on the first turbo encoded codeword through use of aninterleaver, generate a second turbo encoded codeword from theinterleaved codeword through use of a second turbo encoder, and transmitat least a portion of the second turbo encoded codeword. In oneconfiguration, when the intended code rate is determined to be not lessthan the first code rate, the apparatus may be further configured totransmit at least a portion of the first turbo encoded codeword. Theapparatus may be a super encoder as described herein, or a communicationdevice such as a base station, a user equipment (UE), modem or anothersuch device that includes the super encoder.

In another aspect of the disclosure, a method, a computer-readablemedium, and an apparatus are provided. The apparatus may be configuredto receive data, the data including outer turbo encoded, interleaved,inner turbo encoded content. The content may include source data portionand a CRC portion. In some configurations, the apparatus may be furtherconfigured to generate a first decoded instance of the data through useof a first turbo decoder, the first turbo decoder decodes an inner turboencoded portion of the received data, generate a de-interleaved instanceof the data based on the first decoded instance of the data through useof a de-interleaver, and generate a second decoded instance of the datafrom the de-interleaved instance of the data through use of a secondturbo decoder, where the second turbo decoder decodes an outer turboencoded portion of the received data. In some configurations, theapparatus may be further configured to perform a CRC (check) on thesecond decoded instance of the data to determine whether the data issuccessfully received. The apparatus may be a super decoder as describedherein, or a communication device such as a base station, UE, modem oranother such device that includes the super decoder.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating LTE examples of a DLframe structure, DL channels within the DL frame structure, an UL framestructure, and UL channels within the UL frame structure, respectively.

FIG. 3 is a diagram illustrating an example of an evolved Node B (eNB)and UE in an access network.

FIG. 4 illustrates a turbo encoder which may be used in someconfigurations.

FIG. 5 illustrates a block diagram of an example super encoderimplemented in accordance with the features of some configurations.

FIG. 6 illustrates a block diagram of an example super encoder and anexample decoder, in accordance with one configuration.

FIG. 7 is a flowchart of an example method of wireless communication, inaccordance with an example embodiment.

FIG. 8 is a flowchart of another example method of wirelesscommunication, in accordance with another exemplary embodiment.

FIG. 9 is a conceptual data flow diagram illustrating the data flowbetween different means/components in an exemplary apparatus.

FIG. 10 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, etc. (collectively referred to as “elements”).These elements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, and an Evolved Packet Core (EPC) 160. The basestations 102 may include macro cells (high power cellular base station)and/or small cells (low power cellular base station). The macro cellsinclude eNBs. The small cells include femtocells, picocells, andmicrocells.

The base stations 102 (collectively referred to as Evolved UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access Network(E-UTRAN)) interface with the EPC 160 through backhaul links 132 (e.g.,S1 interface). In addition to other functions, the base stations 102 mayperform one or more of the following functions: transfer of user data,radio channel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160) with eachother over backhaul links 134 (e.g., X2 interface). The backhaul links134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacro cells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 and/or downlink (DL)(also referred to as forward link) transmissions from a base station 102to a UE 104. The communication links 120 may use MIMO antennatechnology, including spatial multiplexing, beamforming, and/or transmitdiversity. The communication links may be through one or more carriers.The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10,15, 20 MHz) bandwidth per carrier allocated in a carrier aggregation ofup to a total of Yx MHz (x component carriers) used for transmission ineach direction. The carriers may or may not be adjacent to each other.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL). Thecomponent carriers may include a primary component carrier and one ormore secondary component carriers. A primary component carrier may bereferred to as a primary cell (PCell) and a secondary component carriermay be referred to as a secondary cell (SCell).

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ NR and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing NR in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network.

The millimeter wave (mmW) base station 180 may operate in mmWfrequencies and/or near mmW frequencies in communication with the UE182. Extremely high frequency (EHF) is part of the RF in theelectromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and awavelength between 1 millimeter and 10 millimeters. Radio waves in theband may be referred to as a millimeter wave. Near mmW may extend downto a frequency of 3 GHz with a wavelength of 100 millimeters. The superhigh frequency (SHF) band extends between 3 GHz and 30 GHz, alsoreferred to as centimeter wave. Communications using the mmW/near mmWradio frequency band has extremely high path loss and a short range. ThemmW base station 180 may utilize beamforming 184 with the UE 182 tocompensate for the extremely high path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMES 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService (PSS), and/or other IP services. The BM-SC 170 may providefunctions for MBMS user service provisioning and delivery. The BM-SC 170may serve as an entry point for content provider MBMS transmission, maybe used to authorize and initiate MBMS Bearer Services within a publicland mobile network (PLMN), and may be used to schedule MBMStransmissions. The MBMS Gateway 168 may be used to distribute MBMStraffic to the base stations 102 belonging to a Multicast BroadcastSingle Frequency Network (MBSFN) area broadcasting a particular service,and may be responsible for session management (start/stop) and forcollecting eMBMS related charging information.

The base station may also be referred to as a Node B, evolved Node B(eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (B SS), an extended service set (ESS), or some other suitableterminology. The base station 102 provides an access point to the EPC160 for a UE 104. Examples of UEs 104 include a cellular phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a personaldigital assistant (PDA), a satellite radio, a global positioning system,a multimedia device, a video device, a digital audio player (e.g., MP3player), a camera, a game console, a tablet, a smart device, a wearabledevice, or any other similar functioning device. The UE 104 may also bereferred to as a station, a mobile station, a subscriber station, amobile unit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, a base station (e.g.,base station 180 or 102) and/or the UE 104 may use a super encoder asdescribed herein to encode content to be transmitted (198). For example,in one aspect, a communication device (e.g., base station 180 and/or theUE 104) of the access network 100 may have content to be transmitted(e.g., to another device), where the content may include source dataportion and a CRC portion. The communication device may generate a firstturbo encoded codeword from the content through use of a first turboencoder, where the first turbo encoder may be associated with a firstcode rate. The communication device may determine whether an intendedcode rate for the content to be transmitted is less than the first coderate. In one configuration, when the intended code rate is determined tobe less than the first code rate, the communication device may generatean interleaved codeword based on the first turbo encoded codewordthrough use of an interleaver, generate a second turbo encoded codewordfrom the interleaved codeword through use of a second turbo encoder, andtransmit at least a portion of the second turbo encoded codeword. In oneconfiguration, when the intended code rate is determined to be not lessthan the first code rate, the apparatus may be further configured totransmit at least a portion of the first turbo encoded codeword. Incertain aspects, the communication device (e.g., base station 180 and/orthe UE 104) may use a super decoder as described herein to decodereceived encoded content (198). For example, in one aspect, thecommunication device may receive data including outer turbo encoded,interleaved, inner turbo encoded content. The communication device maygenerate a first decoded instance of the data through use of a firstturbo decoder, where the first turbo decoder decodes an inner turboencoded portion of the received data. The communication device may thengenerate a de-interleaved instance of the data based on the firstdecoded instance of the data through use of a de-interleaver, andgenerate a second decoded instance of the data from the de-interleavedinstance of the data through use of a second turbo decoder, where thesecond turbo decoder decodes an outer turbo encoded portion of thereceived data. In some configurations, the communication device mayperform a CRC on the second decoded instance of the data to determinewhether the data is successfully received/decoded.

FIG. 2A is a diagram 200 illustrating an example of a DL frame structurein LTE. FIG. 2B is a diagram 230 illustrating an example of channelswithin the DL frame structure in LTE. FIG. 2C is a diagram 250illustrating an example of an UL frame structure in LTE. FIG. 2D is adiagram 280 illustrating an example of channels within the UL framestructure in LTE. Other wireless communication technologies may have adifferent frame structure and/or different channels. In LTE, a frame (10ms) may be divided into 10 equally sized subframes. Each subframe mayinclude two consecutive time slots. A resource grid may be used torepresent the two time slots, each time slot including one or more timeconcurrent resource blocks (RBs) (also referred to as physical RBs(PRBs)). The resource grid is divided into multiple resource elements(REs). In LTE, for a normal cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 7 consecutive symbols (for DL,OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a totalof 84 REs. For an extended cyclic prefix, an RB contains 12 consecutivesubcarriers in the frequency domain and 6 consecutive symbols in thetime domain, for a total of 72 REs. The number of bits carried by eachRE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry DL reference (pilot)signals (DL-RS) for channel estimation at the UE. The DL-RS may includecell-specific reference signals (CRS) (also sometimes called common RS),UE-specific reference signals (UE-RS), and channel state informationreference signals (CSI-RS). FIG. 2A illustrates CRS for antenna ports 0,1, 2, and 3 (indicated as R0, R1, R2, and R3, respectively), UE-RS forantenna port 5 (indicated as R5), and CSI-RS for antenna port 15(indicated as R). FIG. 2B illustrates an example of various channelswithin a DL subframe of a frame. The physical control format indicatorchannel (PCFICH) is within symbol 0 of slot 0, and carries a controlformat indicator (CFI) that indicates whether the physical downlinkcontrol channel (PDCCH) occupies 1, 2, or 3 symbols (FIG. 2B illustratesa PDCCH that occupies 3 symbols). The PDCCH carries downlink controlinformation (DCI) within one or more control channel elements (CCEs),each CCE including nine RE groups (REGs), each REG including fourconsecutive REs in an OFDM symbol. A UE may be configured with aUE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCHmay have 2, 4, or 8 RB pairs (FIG. 2B shows two RB pairs, each subsetincluding one RB pair). The physical hybrid automatic repeat request(ARQ) (HARQ) indicator channel (PHICH) is also within symbol 0 of slot 0and carries the HARQ indicator (HI) that indicates HARQ acknowledgement(ACK)/negative ACK (NACK) feedback based on the physical uplink sharedchannel (PUSCH). The primary synchronization channel (PSCH) is withinsymbol 6 of slot 0 within subframes 0 and 5 of a frame, and carries aprimary synchronization signal (PSS) that is used by a UE to determinesubframe timing and a physical layer identity. The secondarysynchronization channel (SSCH) is within symbol 5 of slot 0 withinsubframes 0 and 5 of a frame, and carries a secondary synchronizationsignal (SSS) that is used by a UE to determine a physical layer cellidentity group number. Based on the physical layer identity and thephysical layer cell identity group number, the UE can determine aphysical cell identifier (PCI). Based on the PCI, the UE can determinethe locations of the aforementioned DL-RS. The physical broadcastchannel (PBCH) is within symbols 0, 1, 2, 3 of slot 1 of subframe 0 of aframe, and carries a master information block (MIB). The MIB provides anumber of RBs in the DL system bandwidth, a PHICH configuration, and asystem frame number (SFN). The physical downlink shared channel (PDSCH)carries user data, broadcast system information not transmitted throughthe PBCH such as system information blocks (SIBs), and paging messages.

As illustrated in FIG. 2C, some of the REs carry demodulation referencesignals (DM-RS) for channel estimation at the eNB. The UE mayadditionally transmit sounding reference signals (SRS) in the lastsymbol of a subframe. The SRS may have a comb structure, and a UE maytransmit SRS on one of the combs. The SRS may be used by an eNB forchannel quality estimation to enable frequency-dependent scheduling onthe UL. FIG. 2D illustrates an example of various channels within an ULsubframe of a frame. A physical random access channel (PRACH) may bewithin one or more subframes within a frame based on the PRACHconfiguration. The PRACH may include six consecutive RB pairs within asubframe. The PRACH allows the UE to perform initial system access andachieve UL synchronization. A physical uplink control channel (PUCCH)may be located on edges of the UL system bandwidth. The PUCCH carriesuplink control information (UCI), such as scheduling requests, a channelquality indicator (CQI), a precoding matrix indicator (PMI), a rankindicator (RI), and HARQ ACK/NACK feedback. The PUSCH carries data, andmay additionally be used to carry a buffer status report (BSR), a powerheadroom report (PHR), and/or UCI.

FIG. 3 is a block diagram of an eNB 310 in communication with a UE 350in an access network. In the DL, IP packets from the EPC 160 may beprovided to a controller/processor 375. The controller/processor 375implements layer 3 and layer 2 functionality. Layer 3 includes a radioresource control (RRC) layer, and layer 2 includes a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda medium access control (MAC) layer. The controller/processor 375provides RRC layer functionality associated with broadcasting of systeminformation (e.g., MIB, SIBs), RRC connection control (e.g., RRCconnection paging, RRC connection establishment, RRC connectionmodification, and RRC connection release), inter radio access technology(RAT) mobility, and measurement configuration for UE measurementreporting; PDCP layer functionality associated with headercompression/decompression, security (ciphering, deciphering, integrityprotection, integrity verification), and handover support functions; RLClayer functionality associated with the transfer of upper layer packetdata units (PDUs), error correction through ARQ, concatenation,segmentation, and reassembly of RLC service data units (SDUs),re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto transport blocks(TBs), demultiplexing of MAC SDUs from TBs, scheduling informationreporting, error correction through HARQ, priority handling, and logicalchannel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement layer 1 functionality associated with various signalprocessing functions. Layer 1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal and/or channel condition feedback transmitted bythe UE 350. Each spatial stream may then be provided to a differentantenna 320 via a separate transmitter 318TX. Each transmitter 318TX maymodulate an RF carrier with a respective spatial stream fortransmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The TX processor 368 and the RX processor 356implement layer 1 functionality associated with various signalprocessing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the UE 350. If multiple spatial streams are destined for the UE 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe eNB 310. These soft decisions may be based on channel estimatescomputed by the channel estimator 358. The soft decisions are thendecoded and deinterleaved to recover the data and control signals thatwere originally transmitted by the eNB 310 on the physical channel. Thedata and control signals are then provided to the controller/processor359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the EPC 160. Thecontroller/processor 359 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DLtransmission by the eNB 310, the controller/processor 359 provides RRClayer functionality associated with system information (e.g., MIB, SIBS)acquisition, RRC connections, and measurement reporting; PDCP layerfunctionality associated with header compression/decompression, andsecurity (ciphering, deciphering, integrity protection, integrityverification); RLC layer functionality associated with the transfer ofupper layer PDUs, error correction through ARQ, concatenation,segmentation, and reassembly of RLC SDUs, re-segmentation of RLC dataPDUs, and reordering of RLC data PDUs; and MAC layer functionalityassociated with mapping between logical channels and transport channels,multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the eNB 310 may be used by the TXprocessor 368 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 368 may be provided to different antenna 352 viaseparate transmitters 354TX. Each transmitter 354TX may modulate an RFcarrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB 310 in a manner similar tothat described in connection with the receiver function at the UE 350.Each receiver 318RX receives a signal through its respective antenna320. Each receiver 318RX recovers information modulated onto an RFcarrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the EPC 160. Thecontroller/processor 375 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

There has been an increased interest in enhancing short transmissiontime interval (sTTI) operations in communication systems including LTEand NR systems. While the focus may be enhancing sTTI operations, one ofthe objectives is to support Ultra-Reliable and Low-LatencyCommunications (URLLC) among devices operating in the communicationsystem. Many new and future applications will demand an end-to-endlatency of a few milliseconds, and additionally in many wirelesscommunication fields high transmission reliability is required. Giventhat one of the objectives of LTE URLLC is to enhance transmissionreliability, it is desirable to be able to achieve low mother coderates, e.g., lower than coding rate of 1/3. Furthermore, it is desirableto find solutions where LTE coding schemes may be reused to accomplishthe task of achieving lower code rates, rather than designing andintroducing new coding schemes. Accordingly, various embodimentsdirected to methods and devices that facilitate achieving lower coderates using turbo encoders and turbo coding schemes are disclosed.

FIG. 4 illustrates a turbo encoder 400. As illustrated, the turboencoder 400 includes a first RSC encoder 402, a second RSC encoder 406and an interleave 404 arranged in the illustrated manner. The first andthe second RSC encoders 402, 406 are used in parallel branches as shown.In FIG. 4, “x” represents the input to the turbo encoder 400 which maybe a stream of data bits (e.g., a bit stream). For simplicity, x may beconsidered to be a single bit for example. The output of the turboencoder is illustrated as c1, c2, and c3, where c1 may be the same as x(because the turbo encoder is a systematic coder) while c2 and c3 areparity bits associated with “x”. The coded bits c1, c2, and c3 togethermay be referred to as a codeword (e.g., C1, where C1={c1, c2, c3}) whichis the output of the turbo encoder 400. The code rate of the turboencoder 400 is 1/3. In general, if the code rate for a given encoder isk/n, for every k bits of useful information (e.g., input), the encodergenerates a total of n bits (e.g., as output). Out of the total numberof bits, n-k are redundant.

One way to reduce the coding rate of an encoder, such as the turboencoder 400, may involve adding more parallel branches (of encoders).While adding more parallel branches may help in achieving a lower codingrate, however such an approach at least requires a hardware change whichmay not be desirable. Moreover, another level of complication is addedwith such an approach as to how should additional interleavers bedesigned/chosen to properly increase the weights of the codewords. Thisincreases the overall complexity in implementation since the additionalinterleavers need to be carefully selected, or designed such that theweight of the output codewords increases. Thus, rather than adding morebranches, a better alternative and more effective approach is describedbelow with regard to FIG. 5 that facilitates achieving lower code rateswithout adding complexity.

FIG. 5 illustrates a block diagram of an example super encoder 500,implemented in accordance with the features of some configurations. Theexample super encoder 500 may be used in a variety of communicationsdevices such as base stations, access points, modems, UEs, etc., whichtransmit coded data. The super encoder 500 presents a simple yeteffective approach to achieve lower code rates, e.g., lower than mothercode rate of 1/3 for example. The exemplary super encoder 500 includes afirst turbo encoder 502, an interleaver 504, and a second turbo encoder506. Each of the turbo encoders 502, 506 may be the same as or similarto the turbo encoder 400 shown in FIG. 4, that is, each turbo encodermay include two parallel RSC encoders and an interleaver as shown in theturbo encoder 400.

As illustrated, the two turbo encoders 502 and 506 of the example superencoder 500 are arranged in series in accordance with an aspect. Theexemplary series combination of the turbo encoders 502 and 506, with theinterleaver 504 in between, outputs serially concatenated turbo codes.The first turbo encoder 502 is also referred to as the outer turboencoder and may have a code rate of 1/N in some configurations. Thesecond turbo encoder 506 is also referred to as the inner turbo encoderand may have a code rate of 1/M in some configurations, where M and Nare both positive integers. Continuing with the same example andnotations considered above with regard to FIG. 4, let “x” be the inputto the outer turbo encoder 502 (e.g., input to the super coder 500). Theouter turbo encoder 502 produces the output codeword C1={c1, c2, c3}.The output C1 of the outer turbo encoder 502 is provided as an input tothe interleaver 504. The interleaver 504, used between the outer andinner turbo encoders 502, 506 respectively, serves to scramble thereceived sequence of bits in C1. In an aspect, by using the interleaver504 in the illustrated manner, generation of repeated bits is avoided.The output of the interleaver 504, which is represented as C1′, is fedto the inner turbo encoder 506. The resulting codeword (e.g., alsosometimes referred to as the concatenated code), generated by the innerturbo encoder 506, forms the output of the super encoder 500. In someconfigurations, M equals N. In one particular configuration, M=N=3. Insuch a configuration, the super encoder has an overall resultant coderate of 1/3*1/3=1/9.

In addition to achieving a lower code rate, e.g., code rate of 1/9 inthe case where the code rate of each of the outer and inner turboencoders is 1/3, another advantage of the proposed methods and apparatusis that the overall hamming distance (minimum weight) of theconcatenated code may be increased. For example, if d1 is the distancecorresponding to the outer encoder 502, and d2 is the distancecorresponding to the inner encoder 506, then in accordance with thefeatures of the proposed methods, the distance of the super encoder isD≥d1*d2. Thus, it should be appreciated that in addition to achieving anoverall lower code rate, the minimum weight of the resultingconcatenated code is increased. Increasing the weight of codewords isdesired because an increased minimum weight increases the distance(e.g., hamming distance) between the codewords. As may be appreciated bythose skilled in the art, greater the hamming distance between thecodewords, the better the codewords are, and it is easier to isolatenoise on a receiver end when decoding such codewords.

In accordance with an aspect, to decode the super-code, i.e., theconcatenated code such as produced by the super encoder 500, a receivermay use a decoder that decodes the inner-code first, and then decodesthe outer-code. Since both the inner and outer codes are turbo codes(generated by the inner and outer coders respectively), for decoding theconcatenated code, two serially concatenated turbo decoders may be usedin some configurations. Such a super decoder including seriallyconcatenated turbo decoders is illustrated in FIG. 6 and discussedbelow.

FIG. 6 is a drawing 600 illustrating a block diagram of the exemplarysuper encoder 500 and an exemplary super decoder 601. Drawing 600further illustrates an example of iterative decoding using seriallyconcatenated turbo decoders of the exemplary super decoder 601. Thecomponents/elements as well as the functioning of the super decoder 500has been discussed in detail with respect to FIG. 5 and thus theencoding related discussion will not be repeated. In the illustratedexample configuration of FIG. 6, the super decoder 601 includes an innerturbo decoder 602, a de-interleaver 604 and an outer turbo decoder 606.In accordance with an aspect, the super decoder 601 may receive aconcatenated code and decodes the inner-code first, and then decodes theouter-code. The received signal may include a sequence of modulatedsymbols, e.g., representing outer turbo encoded, interleaved, innerturbo encoded content, e.g., the super coded content. The content mayinclude source data portion and a cyclic redundancy check (CRC) portion.In an aspect, the inner turbo decoder 602 may generate a first decodedinstance of the received data by decoding an inner turbo encoded portionof the received data. The de-interleaver 604 may receive, as an input,the output of the inner turbo decoder 602 to perform the de-interleavingoperation. The output of the de-interleaver 604 may be then fed to theouter turbo decoder 606 which may decode an outer turbo encoded portionof the received data. The decoded data is obtained as the output of theouter turbo decoder 606. If further decoding iterations are not desired,the decoded data output thus obtained from the outer turbo decoder 606may be treated as the result of the decoding operation.

In various configurations, logarithmic-likelihood ratios (LLRs) may beused in the decoding of the received codewords (including the inner andouter codes) to recover the transmitted data. In one configuration, thedecoder 601 may include two serially concatenated Bahl, Cocke, Jelinekand Raviv (BCJR) decoders which iteratively decode the inner/outercodes. It may be noted that the number of iterations may change thedecoding delay. For example, increasing the number of iterations indecoding may provide better decoding results and improve decodingperformance, however increasing the number of iterations also increasesthe decoding delay. As a result, to determine how many iterations aredesired, the performance gain versus decoding delay may be consideredjointly to determine an appropriate tradeoff.

From an implementation perspective, besides the complexity issue, thesuper decoder 601 may pass the LLRs (e.g., corresponding to a receivedcoded bit sequence) between the inner and outer decoders 602 and 606. Inan aspect, if multiple iterations are not desired/performed, theiteration may just be performed once. Furthermore, in someconfigurations, a CRC check/mapping stage(s) may be utilized once thedecoding algorithm converges, e.g., as a result of using iterativedecoding in some configurations. In some other systems which use asingle turbo decoder, the CRC check/mapping stages may be available atthe output of the only decoder.

In accordance with an aspect, the super decoder 601 may pass the LLRs,e.g., corresponding to a given set of input bits, between the inner andouter decoders 602 and 606, for iterative decoding. For a receivedsignal (y), the inner turbo decoder 602 may be provided LLR(y) as aninput. The received signal may include a sequence of modulated symbols,e.g., corresponding to the received outer turbo encoded, interleaved,inner turbo encoded content. LLR(y) may include the log-likelihoodratios (LLRs) corresponding to the received input signal (y), e.g., asequence where each entry of the sequence represents a probability thata given element is a 0 or 1. For iterative decoding, e.g., if iterationsare allowed across the two decoders 602 and 606, the output of the outerdecoder 606 may be sent to the inner decoder 602 as an input.

With reference to FIG. 6, consider an example of iterative decodingusing the serially concatenated turbo decoders 602, 606. The input tothe inner turbo decoder 602 may be provided as the LLR(y) which is asequence of LLRs as discussed above. The inner turbo decoder 602 may beconfigured to update the input LLRs. The output of the inner turbodecoder 602 is shown as O3 which is a sequence of LLRs that are providedto the de-interleaver 604. The de-interleaver 604 outputs O4, which isagain a sequence of LLRs, that are provided as an input to the outerturbo decoder 606. The outer turbo decoder 606 generates updated O4(updated LLRs). If no iterations are further desired, the output of theouter turbo decoder 606 (e.g., updated sequence of LLRs) is mapped to 0and 1s, and this becomes the decoded output from the decoder 601.However, if the decoding scheme is iterative (e.g., more iterations aredesired), then the output of outer turbo decoder 606 (e.g., in the formof updated LLRs) is passed on as an input to the inner turbo decoder602. In the second round/iteration, the decoding is performed using theupdated LLRs which are provided as input to the inner turbo decoder 602and the process may go on if desired. Thus, in each subsequentiteration, updated LLRs may be used in the decoding stages. Thus in thismanner, iterative decoding may be performed (when desired) by exchangingthe LLRs between the inner and outer decoders 602 and 606. In someconfigurations, the steps discussed above in the example may be repeateduntil the decoding algorithm converges. In some configurations, the CRCcheck/mapping stages may be utilized once the decoding algorithmconverges and no more decoding iterations are being performed.

FIG. 7 is a flowchart 700 of an exemplary method of wirelesscommunication, in accordance with an exemplary embodiment. The methodmay be performed by an apparatus, e.g., communication device, includingthe example super encoder as disclosed herein, and/or by elements of anexemplary transmit/receive chain including, e.g., the super encoderdisclosed herein. Such a transmit chain may be used in a variety ofcommunication devices such as base stations, UEs, access points, modemsetc. Some of the operations may be optional as represented bydashed/broken lines. At 702, content to be transmitted is received,e.g., at the super encoder 500. For example, the content to betransmitted may be received from a transmit data buffer (of a devicethat employs the super encoder) where generated content to betransmitted is stored prior to encoding and transmission. In anotherconfiguration, the content to be transmitted may be received at thesuper encoder from an external device. The content may include sourcedata portion and a cyclic redundancy check (CRC) portion. For examplewith reference to FIG. 5, the first (outer) turbo encoder 502 of thesuper encoder 500 may receive the input data to be transmitted asdiscussed above.

At 704, a desired/intended coding rate for the current transmission,e.g., for the content to be transmitted, is determined. Thedesired/intended code rate may be determined based on a number offactors, e.g., such as allowed transmission rate, desired transmissionrate, allocated transmission resources, channel conditions etc. Once theparameters/factors that affect the desired/intended code rate aredetermined, the desired/intended code rate may be determined based onthe above parameters. At 706, it is determined whether theintended/desired code rate is less than a first code rate of a firstturbo encoder being used for encoding the content, e.g., the outer turboencoder 506 of the super coder 500. In some configurations, if at 706the intended/desired code rate is determined to be not less than thefirst code rate (e.g., intended code rate ≥first code rate), thenoperation proceeds to 708.

At 708 a first turbo encoded codeword is generated from the contentthrough use of the first turbo encoder. The first turbo encoder mayinclude a first set of RSC encoders (e.g., such as the two RSC encoders402 and 406) and a first interleaver (e.g., interleaver 404). Forexample, again referring to FIG. 5, the first turbo encoder may be theouter turbo encoder 502 which may be configured to generate the firstturbo encoded codeword from the received content. In someconfigurations, the first turbo encoder encodes the content at a firstcode rate of 1/N to produce the first turbo encoded codeword, where N isa positive integer. In one particular configuration N=3. Next at 710,the first turbo encoded codeword from the first encoder 502 is passed toa rate-matching component which performs rate matching processing. Oneof the main functions of the rate-matching component is to extract theset of bits to be transmitted within a given TTI, e.g., sTTI. Therate-matching for turbo coded codewords may be defined for each codeblock. The output of rate matching component is set of coded bits of thefirst turbo encoded codeword that are extracted for transmission. Afterthe processing by the rate-matching component, at 712 at least a portionof the first turbo encoded codeword is transmitted, e.g., over the airand/or over a wired channel. The portion of the first turbo encodedcodeword that is transmitted comprises the output from the rate matchingcomponent. In some configurations, the portion of the first turboencoded codeword that is transmitted may include the full set of codedbits of the first turbo encoded codeword.

On the other hand, if at 706 the intended/desired code rate isdetermined to be less than the first code rate (e.g., intended code rate<first code rate), then the operation proceeds to 712. In accordancewith an aspect, at 712 a first turbo encoded codeword is generated fromthe content through use of the first turbo encoder. The first turboencoder may include a first set of RSC encoders and a first interleaver.As discussed earlier, the first turbo encoder may be the outer turboencoder 502 (of the super coder 500 of FIG. 5) which may be configuredto generate the first turbo encoded codeword from the received content.In some configurations the first turbo encoder encodes the content at afirst code rate of 1/N to produce the first turbo encoded codeword,where N is a positive integer. Next at 714, the first turbo encodedcodeword from the first encoder is fed to an interleaver that generatesan interleaved codeword based on the first turbo encoded codeword. Forexample, referring to FIG. 5, the output of the outer encoder 502 isprovided to the interleaver 504, where the interleaver 504 may beconfigured to generate an interleaved codeword based on the first turboencoded codeword. At 716, a second turbo encoded codeword is generatedfrom the interleaved codeword through use of a second turbo encoder,e.g., the inner turbo encoder 506 of FIG. 5. In some configurations, thesecond turbo encoder includes a second set of RSC encoders and a thirdinterleaver. Thus, in various configurations, upon a determination thatthe intended code rate is less than the first code rate, the operationmay be controlled to proceed with generation of the interleaved codewordand the second turbo encoded codeword. In some configurations, thesecond turbo encoder encodes the interleaved codeword (i.e., output ofthe second interleaver 504) at a second code rate of 1/M to produce thesecond turbo encoded codeword, where M is a positive integer. Thus byusing the turbo encoders in series in accordance with the disclosedfeatures, an overall code rate of 1/(M*N) is achieved which is lowerthan the first code rate (1/N) and the second code rate (1/M).

Next at 717, the second turbo encoded codeword from the second turboencoder 506 is passed to a rate-matching component which performs ratematching processing. After the processing is performed by therate-matching component, at 718 at least a portion of the second turboencoded codeword is transmitted, e.g., over the air and/or over a wiredchannel. The portion of the second turbo encoded codeword that istransmitted is the output of the rate matching component which mayselect (as part of the rate matching operation) a set of coded bits ofthe second turbo encoded codeword for transmission. The set of codedbits of the second turbo encoded codeword may comprise a subset/portionof the second turbo encoded codeword or the full second turbo encodedcodeword.

FIG. 8 is a flowchart 800 of another exemplary method of wirelesscommunication. The method may be performed by an apparatus such as a UE,base station and/or another communication device that uses a decoder ofthe type disclosed herein, e.g., such as the super decoder 601. Some ofthe operations may be optional as represented by dashed/broken lines. At802, the apparatus may receive data, e.g., a data stream includingcodewords from another device, e.g., a base station or a UE, modem oranother device that transmitted encoded content to the apparatus. Thedata may include outer turbo encoded, interleaved, inner turbo encodedcontent, the content including source data portion and a CRC portion. At804, the apparatus may determine a code rate used for encoding thereceived data. The determination may be based on the information, e.g.,such as resource block allocations and/or modulation and coding scheme(MCS) indication, communicated by the transmitting device. At 805 theapparatus determines if the determined code rate is less than apredetermined threshold code rate, e.g., nominal mother code rate of aturbo encoder (e.g., the first turbo encoder 502) used by thetransmitting device for encoding. The information regarding the nominalmother code rate of the turbo encoder(s) used by the transmitting deviceis known to the apparatus prior to performing decoding operations insome configurations. In various configurations, based on thedetermination at 805, the apparatus selects an appropriate decodingscheme. For example, when the determined code rate is 1/3, the apparatusmay simply decode using a single turbo decoder in the normal manner,otherwise when the determined code rate is <1/3, the apparatusdetermines that a serially concatenated codes need to be decoded andaccordingly selects the exemplary super decoder for decoding.

Thus, when the determined code rate is not less than the predeterminedthreshold code rate, at 806 the apparatus may generate a first decodedinstance of the data through use of a first turbo decoder, e.g., whichmay be the turbo decoder 602. At 808, the apparatus may perform a CRC onthe first decoded instance of the data to determine whether the data issuccessfully received. In some configurations the first turbo decodermay perform multiple iterations before performing the CRC. At 810, theapparatus may transmit an acknowledgement (ACK) or negativeacknowledgement (NACK) based on a result of the performed CRC, e.g.,based on whether CRC indicates that the received data is successfullydecoded or not. When decoding and recovery of the data is successful, anACK may be transmitted, otherwise a NACK may be transmitted.

On the other hand, when the determined code rate is less than thepredetermined threshold code rate, operation proceeds to 812. At 812,the apparatus may generate a first decoded instance of the data throughuse of a first turbo decoder. In various embodiments the first turbodecoder decodes an inner turbo encoded portion of the received data. Forexample, with reference to FIG. 6, the first turbo decoder may be theinner turbo decoder 602 that may decode the inner code of the receivedcodeword in the manner discussed above with regard to FIG. 6.

Next, at 814, the apparatus may generate a de-interleaved instance ofthe data based on the first decoded instance of the data through use ofa de-interleaver. At 816 the apparatus may generate a second decodedinstance of the data from the de-interleaved instance of the datathrough use of a second turbo decoder. In some configurations, thesecond turbo decoder decodes an outer turbo encoded portion of thereceived data. For example, with reference to FIG. 6, the second turbodecoder may be the outer turbo decoder 606 that may decode the outercode of the received codeword.

In some configurations, the decoding operation may be performediteratively for improved decoding results. In an aspect, a number ofiterations to be performed may be determined based on a decodingperformance gain from the number of iterations and a decoding delayresulting from the number of iterations. In some such configurations,multiple iterations may be performed across the first and second turbodecoders until the decoding converges. In one such configuration, theapparatus may be further configured to generate a second iteration ofthe first decoded instance, based on the second decoded instancegenerated by the second turbo decoder, through use of the first turbodecoder. The apparatus may be further configured to generate a seconditeration of the de-interleaved instance of the data, based on thesecond iteration of the first decoded instance of the data, through useof the de-interleaver. The apparatus may be further configured togenerate a second iteration of the second decoded instance of the datafrom the second iteration of the de-interleaved instance of the datathrough use of the second turbo decoder. For example, the apparatus mayinclude the decoder 601 of FIG. 6 for performing decoding operation andthe decoder 601 may pass the LLRs, between the inner and outer decoders602 and 606 for iterative decoding as discussed in detail in connectionwith FIG. 6. In some configurations, a number of iterations of the firstdecoded instance and the second decoding instance to be generated isdetermined as a function of a decoding performance gain from the numberof iterations and a decoding delay resulting from the number ofiterations.

At 818, the apparatus may perform a CRC on the second decoded instanceof the data to determine whether the data is successfully received. Insome configurations the CRC check/mapping may be performed when thedecoding converges. At 820, the apparatus may transmit anacknowledgement (ACK) or negative acknowledgement (NACK) based on aresult of the performed CRC. For example, in some configurations, if thereceived data is successfully decoded and recovered, then an ACK may betransmitted, otherwise a NACK may be transmitted.

FIG. 9 is a conceptual data flow diagram 900 illustrating the data flowbetween different means/components in an example apparatus 902. Theapparatus 902 may be a device (e.g., such as base station 102/180/310,UE 104/350, a modem, or another communication device) that may employthe super encoder and/or the super decoder described supra. Theapparatus 902 may include a reception component 904, a transmit databuffer/storage component 906, a determination component 908, a superencoder/encoding component 910, a rate matching component 912, a superdecoder/decoding component 914, and a transmission component 916. In theillustrated configuration, the apparatus 902 includes both a superencoder and a super decoder. However, in some other configurations theapparatus 902 may include one of the super encoder or the super decoder.

The reception component 904 may be configured to receive messages and/orother information from other devices including, e.g., communicationdevice 950 which may be a base station, UE, modem, or another suchdevice. The communication device 950 may also include the super encoder500 and/or decoder 601 described supra. The signals/information receivedby the reception component 904 may be provided to one or more componentsof the apparatus 902 for further processing and use in performingvarious operations in accordance with the methods discussed supraincluding the method of flowcharts 700 and 800. In some configurations,the reception component 904 may receive (e.g., from another input deviceor external source) content to be transmitted which may then be storedin the transmit data buffer 906 prior to being supplied to the superencoder for encoding. The content may include source data portion and aCRC portion. In some other configurations, the content to be transmittedmay be generated by the apparatus 902 and stored in the transmit databuffer 906 prior to being supplied to the super encoder for encoding inaccordance with the proposed methods described herein. The receptioncomponent 904 may be further configured to receive data, e.g., from thecommunication device 950, where the data may include encoded content,e.g., outer turbo encoded, interleaved, inner turbo encoded content. Thecontent may include source data portion and a CRC portion. The receivedencoded data may be provided from the reception component 904 to thesuper decoder 914 for decoding in accordance with the proposed methodsdescribed herein.

The super encoder 910 may be the super encoder 500 shown FIGS. 5-6, andmay perform the same functions discussed earlier with respect to superencoder 500. For example, the super encoder 910 may include the first(outer) turbo encoder 502, the interleaver 504, and the second (inner)turbo encoder 506. The first (outer) turbo encoder 502 may have a firstcode rate of 1/N and the second (inner) turbo encoder 506 may have asecond code rate of 1/M in some configurations, where M and N are bothpositive integers. The determination component 908 may be configured todetermine whether an intended code rate is less than the first code rate(e.g., nominal mother code rate of the first turbo encoder 502), andprovide the result of determination to the super encoder 910. Thedetermination may be performed based on number of factors/parameters,e.g., such as allowed transmission rate, desired transmission rate,allocated transmission resources, channel conditions etc. Some suchfactors/parameters may be preconfigured and/or determined by thedetermination component 908 based on configuration/control informationreceived from the communication device 950. The determination component908 may provide the result of the determination to the super encoder910. When the determined information from the determination component908 indicates that the intended/desired code rate is equal to or greaterthan the first code rate of the first turbo encoder 502 (e.g., intendedcode rate ≥first code rate), the super encoder 910 may generate, usingthe first turbo encoder 502, a first turbo encoded codeword from thecontent to be transmitted, and in this case the first turbo encodedcodeword forms the output of the super encoder 910. On the other hand,when the determined information from the determination component 908indicates that the intended/desired code rate is less than the firstcode rate of the first turbo encoder 502, the super encoder 910 mayfirst generate a first turbo encoded codeword from the content throughuse of the first turbo encoder, then the first turbo encoded codewordfrom the first encoder is fed to the interleaver 505 that generates aninterleaved codeword based on the first turbo encoded codeword, andfinally a second turbo encoded codeword is generated from theinterleaved codeword through use of the second turbo encoder 506. In thesecond case, the second turbo encoded codeword becomes the output of thesuper encoder 910. Thus, depending on the whether the desired code rateis less than the mother code rate of the first encoder 502 of the superencoder 910, the super encoder 910 may output either the first turboencoded codeword or the second turbo encoded codeword (e.g., shown asoutput turbo encoded codeword in FIG. 9). The turbo encoded codeword maythen be supplied to the rate matching component 912.

The rate matching component 912 may be configured to perform ratematching operation on the output turbo encoded codeword received fromthe super encoder 910. The output from the rate matching component 912,e.g., rate matched output, is provided to the transmission component 916for transmission. The rate matched output may comprise at least aportion of the turbo encoded codeword from the super encoder 910.

When the apparatus 902 receives (via the reception component 904)encoded content from the communication device 950, the received contentmay be provided to the super decoder 914 for decoding. The super decoder914 may be the super decoder 601 shown FIG. 6, and may perform the samefunctions discussed earlier with respect to super decoder 601. Forexample, the super decoder 910 may include the inner turbo decoder 602,the de-interleaver 604, and the outer turbo decoder 606, and may beconfigured to perform decoding in accordance with the decoding processillustrated in the flowchart 800. In the case when decoding of receiveddata needs to be performed, the determination component 908 maydetermine a code rate that may have been used for encoding the receiveddata. Such determination may be based on control information, e.g.,resource allocation and/or MCS indication, received from thecommunication device 950 that transmitted the encoded data. Thedetermination component 908 may be further configured to determinewhether the determined code rate is less than a predetermined thresholdcode rate, e.g., nominal mother code rate of a turbo encoder (e.g., thefirst turbo encoder 502) used by the transmitting device (e.g.,communication device 950) for encoding. The result of determination(e.g., information indicating whether code rate is less than thresholdcode rate) is then passed on to the super decoder 914, and the superdecoder 914 may decide how to perform decoding based on the determinedcode rate.

For example, when the determined code rate is not less than the nominalmother code rate (e.g., ˜1/3) of a turbo encoder (e.g., the first turboencoder 502 that may also be used by the transmitting device 950 forencoding), the super decoder 914 may decode the encoded content using asingle turbo decoder of the super decoder 914. When the determined coderate is less than the threshold code rate (e.g., <1/3), the superdecoder 914 may understand that serially concatenated codes need to bedecoded and accordingly may perform decoding using the two turbodecoders of the super decoder 914. In this case, the super decoder 914may first generate a first decoded instance of the data through use ofthe first turbo decoder 602 (which may decode the inner code of thecodeword), then generate a de-interleaved instance of the data based onthe first decoded instance of the data through use of the de-interleaver604, and generate a second decoded instance of the data from thede-interleaved instance of the data through use of the second turbodecoder 606 (which may decode the outer code of the codeword).

In some configuration, the super decoder 914 may be configured toperform iterative decoding (e.g., perform multiple iterations) in themanner discussed above in connection with FIG. 6. The number ofiterations to be performed may be determined (e.g., by the super decoder914 or controller/processor of apparatus 902) based on a decodingperformance gain from the number of iterations and a decoding delayresulting from the number of iterations. In some such configurations,multiple iterations may be performed across the first and second turbodecoders 602, 606 of the until the decoding converges. In one suchconfiguration, super decoder 914 may generate a second iteration of thefirst decoded instance, from the second decoded instance generated bythe second turbo decoder 606, through use of the first turbo decoder602. The super decoder 914 may further generate a second iteration ofthe de-interleaved instance of the data, based on the second iterationof the first decoded instance of the data, through use of thede-interleaver 604. Subsequently, the super decoder 914 may furthergenerate a second iteration of the second decoded instance of the datafrom the second iteration of the de-interleaved instance of the datathrough use of the second turbo decoder 606. For example, the superdecoder 914 may pass the LLRs, e.g., corresponding to bits of inputdata, between the inner and outer decoders 602 and 606 for iterativedecoding as discussed in detail in connection with FIG. 6.

Once decoding operation is complete (e.g., when the decoding converges),a CRC operation may be performed on the decoded output data. In someconfigurations, the super decoder 914 may include a CRC component (notshown separately) for performing the CRC, or alternatively the CRCcomponent may be external to the super decoder 914. In the apparatus902, the CRC component may be considered to be a part of the superdecoder 914. In the example case of a single iteration decoding ofreceived encoded data which includes a serially concatenated code, thesecond decoded instance of the data (generated by the second turbodecoder 606 as discussed above) may be the decoding output. In such anexample case, the super decoder 914 may perform (e.g., using the CRCcomponent) a CRC on the second decoded instance of the data to determinewhether the data is successfully received. In other cases where multipleiterations may be performed, the CRC may be performed on the finaldecoding output generated after multiple decoding iterations.

If the CRC is successful, the decoded output data may be stored and/orprovided to other components of the apparatus for processing and/or use.If the CRC is unsuccessful, the apparatus 902 may request retransmissionof the received content from the communication device 950. In someconfigurations, an indication of the result of CRC determination(decoding success/failure indication) is provided to the transmissioncomponent 916 Based on such indication, the transmission component 916may be configured to generate and transmit an acknowledgement (ACK) ornegative acknowledgement (NACK) to the communication device 950.

The transmission component 916 may be configured to transmit turboencoded codewords, ACK/NACK feedback(s), and/or other information to oneor more external devices, e.g., communication device 950. For example,in some configurations where the apparatus 902 has turbo encoded datafor transmission, the transmission component 916 may be configured totransmit at least a portion of the turbo encoded codeword (after ratematching has been performed on the turbo encoded codeword produced bythe super encoder) to the communication device 950.

In one configuration, the transmission component 916 may be configuredto transmit at least a portion of a first turbo encoded codeword, wherethe first turbo encoded codeword may be generated by a first turboencoder, e.g., such as the first turbo encoder 502 of the super encoder500. In one configuration, the transmission component 916 may beconfigured to transmit at least a portion of a second turbo encodedcodeword, where the second turbo encoded codeword may be generated by asecond turbo encoder, e.g., such as the second turbo encoder 506 of thesuper encoder 500.

In some configurations, where the apparatus 902 performs decoding onreceived encoded data, the transmission component 916 may be configuredto transmit an acknowledgement (ACK) or negative acknowledgement (NACK)based on a result of the CRC operation discussed above in connectionwith the decoding operation. In one configuration, the transmissioncomponent 916 may be configured to generate and transmit an ACK when thereceived data is successfully decoded, and transmit a NACK when thedecoding is unsuccessful.

The apparatus may include additional components that perform each of theblocks of the algorithm in the aforementioned flowchart of FIG. 10. Assuch, each block in the aforementioned flowchart of FIG. 10 may beperformed by a component and the apparatus may include one or more ofthose components. The components may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

FIG. 10 is a diagram 1000 illustrating an example of a hardwareimplementation for an apparatus 902′ employing a processing system 1014.The processing system 1010 may be implemented with a bus architecture,represented generally by the bus 1024. The bus 1024 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1014 and the overall designconstraints. The bus 1024 links together various circuits including oneor more processors and/or hardware components, represented by theprocessor 1004, the components 904, 906, 908, 910, 912, 914, 916 and thecomputer-readable medium/memory 1006. The bus 1024 may also link variousother circuits such as timing sources, peripherals, voltage regulators,and power management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 1014 may be coupled to a transceiver 1010. Thetransceiver 1010 is coupled to one or more antennas 1020. Thetransceiver 1010 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1010 receives asignal from the one or more antennas 1020, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1014, specifically the reception component 904. Inaddition, the transceiver 1010 receives information from the processingsystem 1014, specifically the transmission component 916, and based onthe received information, generates a signal to be applied to the one ormore antennas 1020. The processing system 1014 includes a processor 1004coupled to a computer-readable medium/memory 1006. The processor 1004 isresponsible for general processing, including the execution of softwarestored on the computer-readable medium/memory 1006. The software, whenexecuted by the processor 1004, causes the processing system 1014 toperform the various functions described supra for any particularapparatus. The computer-readable medium/memory 1006 may also be used forstoring data that is manipulated by the processor 1004 when executingsoftware. The processing system 1014 further includes at least one ofthe components 904, 906, 908, 910, 912, 914, and 916. The components maybe software components running in the processor 1004, resident/stored inthe computer-readable medium/memory 1006, one or more hardwarecomponents coupled to the processor 1004, or some combination thereof.

In one configuration, the apparatus 902/902′ for wireless communicationmay comprise means for receiving content to be transmitted, the contentincluding source data portion and a CRC portion. The apparatus 902/902′may further comprise means for generating a first turbo encoded codewordfrom the content, where the means for generating the first turbo encodedcodeword may include a first set of RSC encoders and a firstinterleaver. The apparatus 902/902′ may further comprise means forgenerating an interleaved codeword based on the first turbo encodedcodeword, and means for generating a second turbo encoded codeword fromthe interleaved codeword, the means for generating the second turboencoded codeword may include a second set of RSC encoders and a secondinterleaver. The apparatus may further include means for transmitting atleast a portion of the second turbo encoded codeword. In oneconfigurations, the means for generating the first turbo encodedcodeword and the means for generating the second turbo encoded codewordare in series with each other separated by the means for generating theinterleaved codeword. In one configuration, the apparatus may furthercomprise means for determining whether an intended (e.g., desired) coderate for transmission of the content to be transmitted is less than thefirst code rate. In one configuration, when the intended code rate isdetermined to be not less than the first code rate, the means fordetermining may be configured to control the means for generating thefirst turbo encoded codeword to pass the first turbo encoded codeword toa rate-matching component.

In some configurations, the means for receiving is further configured toreceive data including outer turbo encoded, interleaved, inner turboencoded content, the content including source data portion and a CRCportion. In some such configurations, the apparatus 902/902′ may furthercomprise means for generating a first decoded instance of the data, themeans for generating the first decoded instance of the data decoding aninner turbo encoded portion of the received data. The apparatus 902/902′may further comprise means for generating a de-interleaved instance ofthe data based on the first decoded instance of the data. The apparatus902/902′ may further comprise means for generating a second decodedinstance of the data from the de-interleaved instance of the data, themeans for generating the second decoded instance of the data decoding anouter turbo encoded portion of the received data. In one configuration,the apparatus 902/902′ may further comprise means for performing a CRCon the second decoded instance of the data to determine whether the datais successfully received. In one configuration, the means fortransmitting is further configured to transmit an acknowledgement (ACK)or negative acknowledgement (NACK) based on a result of the performedCRC. In one configuration, the means for generating the first decodedinstance is further configured to generate a second iteration of thefirst decoded instance, based on the second decoded instance generatedby the second turbo decoder. In one configuration, the means forgenerating the de-interleaved instance is further configured to generatea second iteration of the de-interleaved instance of the data, based onthe second iteration of the first decoded instance of the data. In oneconfiguration, the means for generating the second decoded instance isfurther configured to generate a second iteration of the second decodedinstance of the data from the second iteration of the de-interleavedinstance of the data. In some configurations, the number of iterationsof the first decoded instance and the second decoding instance to begenerated is determined as a function of a decoding performance gainfrom the number of iterations and a decoding delay resulting from thenumber of iterations.

In one configuration, the processing system 1014 may be a component ofthe UE 350 and may include the memory 360 and/or at least one of the TXprocessor 368, the RX processor 356, and the controller/processor 359.The aforementioned means may be one or more of the aforementionedcomponents of the apparatus 902 and/or the processing system 1014 of theapparatus 902′ configured to perform the functions recited by theaforementioned means. As described supra, the processing system 1014 mayinclude the TX Processor 368, the RX Processor 356, and thecontroller/processor 359. As such, in one configuration, theaforementioned means may be the TX Processor 368, the RX Processor 356,and the controller/processor 359 configured to perform the functionsrecited by the aforementioned means.

In another configuration, the processing system 1014 may be a componentof the base station 310 and may include the memory 376 and/or at leastone of the TX processor 316, the RX processor 370, and thecontroller/processor 375. As such, in such a configuration, theaforementioned means may be the TX Processor 316, the RX Processor 370,and the controller/processor 375 configured to perform the functionsrecited by the aforementioned means.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flowcharts may berearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “one or more of A, B, or C,” “at least oneof A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or anycombination thereof” include any combination of A, B, and/or C, and mayinclude multiples of A, multiples of B, or multiples of C. Specifically,combinations such as “at least one of A, B, or C,” “one or more of A, B,or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and“A, B, C, or any combination thereof” may be A only, B only, C only, Aand B, A and C, B and C, or A and B and C, where any such combinationsmay contain one or more member or members of A, B, or C. All structuraland functional equivalents to the elements of the various aspectsdescribed throughout this disclosure that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the claims.Moreover, nothing disclosed herein is intended to be dedicated to thepublic regardless of whether such disclosure is explicitly recited inthe claims. The words “module,” “mechanism,” “element,” “device,” andthe like may not be a substitute for the word “means.” As such, no claimelement is to be construed as a means plus function unless the elementis expressly recited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communications, comprising:receiving content to be transmitted, the content including source dataportion and a cyclic redundancy check (CRC) portion; generating a firstturbo encoded codeword from the content through use of a first turboencoder, wherein the first turbo encoder is associated with a first coderate; and determining whether an intended code rate for the content tobe transmitted is less than the first code rate; wherein when theintended code rate is determined to be less than the first code rate,the method further comprises: generating an interleaved codeword basedon the first turbo encoded codeword through use of an interleaver;generating a second turbo encoded codeword from the interleaved codewordthrough use of a second turbo encoder; and transmitting at least aportion of the second turbo encoded codeword.
 2. The method of claim 1,further comprising: pass the second turbo encoded codeword to arate-matching component for rate matching, wherein the portion of thesecond turbo encoded codeword that is transmitted is an output of therate matching component.
 3. The method of claim 1, wherein first turboencoder encodes the content at the first code rate of 1/N to produce thefirst turbo encoded codeword, N being a positive integer.
 4. The methodof claim 3, wherein the second turbo encoder encodes the interleavedcodeword at a second code rate of 1/M to produce the second turboencoded codeword, M being a positive integer, and resulting in anoverall code rate for the second turbo encoded codeword of 1/(M*N). 5.The method of claim 1, wherein the first and second turbo encoders arein series with each other separated by the interleaver.
 6. The method ofclaim 1, wherein when the intended code rate is not less than the firstcode rate, the method further comprises: passing the first turbo encodedcodeword to a rate-matching component; and transmitting at least aportion of the first turbo encoded codeword.
 7. The method of claim 6,wherein the portion of the first turbo encoded codeword is an output ofthe rate matching component.
 8. The method of claim 1, wherein the firstturbo encoder includes a first set of recursive systematic convolutional(RSC) encoders and a second interleaver, and wherein the second turboencoder includes a second set of RSC encoders and a third interleaver.9. An apparatus for wireless communications, comprising: a memory; andat least one processor coupled to the memory and configured to: receivecontent to be transmitted, the content including source data portion anda cyclic redundancy check (CRC) portion; generate a first turbo encodedcodeword from the content through use of a first turbo encoder, whereinthe first turbo encoder is associated with a first code rate; anddetermine whether an intended code rate for the content to betransmitted is less than the first code rate; wherein when the intendedcode rate is determined to be less than the first code rate, the atleast one processor is further configured to: generate an interleavedcodeword based on the first turbo encoded codeword through use of aninterleaver; generate a second turbo encoded codeword from theinterleaved codeword through use of a second turbo encoder; and transmitat least a portion of the second turbo encoded codeword.
 10. Theapparatus of claim 9, wherein the at least one processor is furtherconfigured to: pass the second turbo encoded codeword to a rate-matchingcomponent for rate matching, wherein the portion of the second turboencoded codeword that is transmitted is an output of the rate matchingcomponent.
 11. The apparatus of claim 9, wherein first turbo encoderencodes the content at the first code rate of 1/N to produce the firstturbo encoded codeword, N being a positive integer.
 12. The apparatus ofclaim 9, wherein the second turbo encoder encodes the interleavedcodeword at a second code rate of 1/M to produce the second turboencoded codeword, M being a positive integer, and resulting in anoverall code rate for the second turbo encoded codeword of 1/(M*N). 13.The apparatus of claim 9, wherein the first and second turbo encodersare in series with each other separated by the interleaver.
 14. Theapparatus of claim 9, wherein when the intended code rate is not lessthan the first code rate, the at least one processor is furtherconfigured to: pass the first turbo encoded codeword to a rate-matchingcomponent; and transmitting at least a portion of the first turboencoded codeword.
 15. The apparatus of claim 9, wherein the first turboencoder includes a first set of recursive systematic convolutional (RSC)encoders and a second interleaver, and wherein the second turbo encoderincludes a second set of RSC encoders and a third interleaver.
 16. Amethod of wireless communications, comprising: receiving data, the dataincluding outer turbo encoded, interleaved, inner turbo encoded content,the content including source data portion and a cyclic redundancy check(CRC) portion; generating a first decoded instance of the data throughuse of a first turbo decoder, the first turbo decoder decodes an innerturbo encoded portion of the received data; generating a de-interleavedinstance of the data based on the first decoded instance of the datathrough use of a de-interleaver; generating a second decoded instance ofthe data from the de-interleaved instance of the data through use of asecond turbo decoder, the second turbo decoder decodes an outer turboencoded portion of the received data; and performing a CRC on the seconddecoded instance of the data to determine whether the data issuccessfully received.
 17. The method of claim 16, further comprising:transmitting an acknowledgement (ACK) or negative acknowledgement (NACK)based on a result of the performed CRC.
 18. The method of claim 16,wherein the ACK is transmitted when the performed CRC is successfulindicating successful decoding of the data, and wherein the NACK istransmitted when the performed CRC fails.
 19. The method of claim 16,wherein the first turbo decoder and the second turbo decoder eachincludes Bahl, Cocke, Jelinek and Raviv (BCJR) decoders.
 20. The methodof claim 16, wherein the first turbo decoder and second turbo decoderare in series with each other.
 21. The method of claim 16, wherein thefirst decoded instance of the data is provided to the de-interleaver aslogarithmic likelihood ratios (LLRs).
 22. The method of claim 16,further comprising: generating a second iteration of the first decodedinstance, based on the second decoded instance generated by the secondturbo decoder, through use of the first turbo decoder; generating asecond iteration of the de-interleaved instance of the data, based onthe second iteration of the first decoded instance of the data, throughuse of the de-interleaver; and generating a second iteration of thesecond decoded instance of the data from the second iteration of thede-interleaved instance of the data through use of the second turbodecoder.
 23. The method of claim 22, wherein a number of iterations ofthe first decoded instance and the second decoding instance to begenerated is determined as a function of a decoding performance gainfrom the number of iterations and a decoding delay resulting from thenumber of iterations.
 24. An apparatus for wireless communications,comprising: a memory; and at least one processor, coupled to the memory,and configured to: receive data, the data including outer turbo encoded,interleaved, inner turbo encoded content, the content including sourcedata portion and a cyclic redundancy check (CRC) portion; generate afirst decoded instance of the data through use of a first turbo decoder,the first turbo decoder decodes an inner turbo encoded portion of thereceived data; generate a de-interleaved instance of the data based onthe first decoded instance of the data through use of a de-interleaver;generate a second decoded instance of the data from the de-interleavedinstance of the data through use of a second turbo decoder, the secondturbo decoder decodes an outer turbo encoded portion of the receiveddata; and perform a CRC on the second decoded instance of the data todetermine whether the data is successfully received.
 25. The apparatusof claim 24, wherein the at least one processor is further configuredto: transmit an acknowledgement (ACK) or negative acknowledgement (NACK)based on a result of the performed CRC.
 26. The apparatus of claim 24,wherein the first turbo decoder and the second turbo decoder eachincludes Bahl, Cocke, Jelinek and Raviv (BCJR) decoders.
 27. Theapparatus of claim 24, wherein the first turbo decoder and second turbodecoder are in series with each other.
 28. The apparatus of claim 24,wherein the first decoded instance of the data is provided to thede-interleaver as logarithmic likelihood ratios (LLRs).
 29. Theapparatus of claim 24, wherein the at least one processor is furtherconfigured to: generate a second iteration of the first decodedinstance, based on the second decoded instance generated by the secondturbo decoder, through use of the first turbo decoder; generate a seconditeration of the de-interleaved instance of the data, based on thesecond iteration of the first decoded instance of the data, through useof the de-interleaver; and generate a second iteration of the seconddecoded instance of the data from the second iteration of thede-interleaved instance of the data through use of the second turbodecoder.
 30. The apparatus of claim 29, wherein a number of iterationsof the first decoded instance and the second decoding instance to begenerated is determined as a function of a decoding performance gainfrom the number of iterations and a decoding delay resulting from thenumber of iterations.